Impact of cultivar and seasonal growing conditions on growth and health-promoting compounds in Brassica oleracea cultivars: Smooth German kale, Scarlet kale, Dwarf Blue Curled kale, and Collard

Abstract

The present study analyzed the effects of growing season and cultivar type on the health-promoting compounds of four leafy cabbage cultivars: Collard, Scarlet, Smooth, and Curled. The results revealed that all growth parameters, including glucosinolate (GLS) content, flavonoid content, and phenol content, were higher in spring than in autumn. All cultivars had relatively high levels of glucoraphanin, gluconapin, and glucobrassicin, as well as low levels of progoitrin and gluconasturtiin. The abscisic acid (ABA) and antioxidant enzyme content were not season-dependent and differed significantly by cultivar. Total non-essential AA accounted for the highest percentage of amino acids (AA) at 57.2 %, while total sulfur AA had the lowest value at 7.41 %. Generally, leafy cabbage has better nutraceutical and health-promoting compounds in the spring growing season than in autumn. It seems that Collard had better vegetative growth characteristics, and Scarlet showed better phytochemical compounds. These findings suggest that optimizing the cultivation of leafy cabbage in spring could maximize the health benefits for consumers. Future research should focus on the mechanisms behind seasonal variations in phytochemical content and the long-term health impacts of these compounds.